Abstract
Obesity is associated with altered food-related reward processing, but its impact on non-food reward remains unclear. This question is both timely due to rising rates of severe obesity and important because adolescence is a period of heightened reward seeking behavior. We used computational modeling and functional magnetic resonance imaging to examine monetary reward processing using classic experimental tasks in 35 adolescents (14-18 years-old, 13 male) with severe obesity (n=18) and without obesity (n=17). Participants completed the Balloon Analog Risk Taking Task to assess reward-related decision-making and the Monetary Incentive Delay task to assess neural correlates of reward anticipation. Reward-related decision-making model parameters revealed no differences in reward sensitivity but less adaptive decision-making (response consistency) in those with obesity compared to without obesity. Other metrics (e.g., number of balloons popped, number of pumps, and total points) did not differ between groups. During reward anticipation, those with obesity had lower activation than without obesity in ventral tegmental area and prefrontal cortex, canonical regions for reward and cognitive control, respectively. Weight status moderated associations between ventral tegmental area activation and reward-related decision-making metrics such that higher ventral tegmental area activation was associated with more risky decision-making (more popped balloons) in those with but not without obesity. Functional connectivity of ventral tegmental area with right inferior frontal gyrus and left superior temporal gyrus was greater higher in OB than nonOB. Associations between value-related ventral tegmental area-superior temporal gyrus connectivity and reward-related decision-making metrics were moderated by weight status such that higher connectivity was associated with greater number of pumps and points for without obesity and less risky decision-making for those with obesity. Therefore, differences in activation and connectivity between groups may suggest differences in decision-making strategies. Together, findings reveal that ventral tegmental area, prefrontal, and temporal engagement during monetary reward anticipation differs between adolescents with and without obesity and may contribute to individual differences in reward-related decision-making. Such domain-general alteration of reward processing may have far reaching consequences, not only for food intake but also functions central to motivational behavior such as learning and socialization during adolescence, a sensitive period in development. These findings highlight the importance of considering reward more broadly when designing and tailoring behavioral interventions in adolescent obesity.